(a) Field of the Invention
The present invention relates to an apparatus that is commonly applicable to a gas-liquid separating process using a reboiling device. More particularly, the present invention relates to the reboiling device and a regeneration tower provided with the same that are used in a regeneration process of a boiling type in order to regenerate and reuse saturated absorbent liquid containing gas that is a removing object.
(b) Description of the Related Art
Recently, a technique for suppressing release of carbon dioxide into the atmosphere has been developed in order to counteract the effects of global warming and air pollution. Particularly, methods of efficiently trapping carbon dioxide emitted from thermoelectric power plants or boiler equipment have been developed.
Among various methods of trapping gas, it is widely known that a chemical absorption method using absorbent liquid is most suitable to trapping carbon dioxide of large capacity. According to the chemical absorption method, carbon dioxide emitted from thermoelectric power plants or boiler equipment is absorbed in absorbent liquid in an absorption tower, and saturated absorbent liquid containing carbon dioxide is heated in a regeneration tower so as to separate the carbon dioxide from the absorbent liquid.
A reboiler for heating the absorbent liquid is mounted at the regeneration tower as an energy source for regeneration. The reboiler heats the absorbent liquid up to a temperature at which the regeneration is possible so as to separate the gas contained in the absorbent liquid. The gas separated from the absorbent liquid moves to an upper portion of the regeneration tower such that useful material is collected into a condenser and the gas that is removing object is discharged from the regeneration tower.
Conventionally, a reboiler of kettle type or a reboiler of thermocyphon type is used.
The reboiler of kettle type includes first and second parts therein divided by a wall. A heater or a heat-exchanger is disposed in the first part, and an absorbent liquid outlet is formed at the second part. If the absorbent liquid containing the gas is supplied to an upper portion of the reboiler, a level of the absorbent liquid in the reboiler rises. At this time, the absorbent liquid is heated by the heater or the heat-exchanger, and the gas is separated from the absorbent liquid and moves upwardly. As the absorbent liquid is supplied continuously, the absorbent liquid from which the gas is removed or which contains less gas crosses the wall and moves to the second part. After that, the absorbent liquid is discharged from the reboiler through the absorbent liquid outlet. According to the reboiler of kettle type, slosh occurs due to liquid wave generated by liquid drop and boiling of mixed liquid. Therefore, it is very difficult to control a level of the absorbent liquid precisely.
The reboiler of thermocyphon type includes a heater or a heat-exchanger therein, and an absorbent liquid outlet is formed at a bottom surface of the reboiler. If the absorbent liquid containing the gas is supplied to an upper portion of the reboiler, the absorbent liquid in the reboiler is heated by the heater or the heat-exchanger, and the gas is separated from the absorbent liquid and moves upwardly. At this time, the absorbent liquid from which the gas is removed or which contains less gas moves toward the bottom surface of the reboiler and is discharged from the reboiler through the absorbent liquid outlet. According to the reboiler of thermocyphon type, it is difficult to control a level of the absorbent liquid due to boiling. In addition, since there is no wall in the boiler, the mixed liquid remains in the reboiler for a very short time. Therefore, less energy is supplied to the mixed liquid, and gas separation efficiency for regeneration is very low.
In addition, a supply path of the mixed liquid and a discharge path of the gas separated from the mixed liquid are the same in the reboiler of kettle type and the reboiler of thermocyphon type. Therefore, if bubbles occur due to heating, the mixed liquid cannot reach the heater or the heat-exchanger by the bubbles. If this condition continues, the level of the mixed liquid in the regeneration tower is raised too high such that the absorption tower and the regeneration tower cannot work properly.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.